Cod sursa(job #2190529)

Utilizator pepsiM4A1Ozturk Arif pepsiM4A1 Data 31 martie 2018 01:05:29
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 2.99 kb
#include <iostream>
#include <fstream>
#include <cstring>
#include <algorithm>
#include <memory>

#define NMAX 100005

using namespace std;

class Reader {
  public:
    Reader(const string& filename):
            m_stream(filename),
            m_pos(kBufferSize - 1),
            m_buffer(new char[kBufferSize]) {
        next();
    }

    Reader& operator>>(int& value) {
        value = 0;
        while (current() < '0' || current() > '9')
            next();
        while (current() >= '0' && current() <= '9') {
            value = value * 10 + current() - '0';
            next();
        }
        return *this;
    }

  private:
    const int kBufferSize = 32768;

    char current() {
        return m_buffer[m_pos];
    }

    void next() {
        if (!(++m_pos != kBufferSize)) {
            m_stream.read(m_buffer.get(), kBufferSize);
            m_pos = 0;
        }
    }

    ifstream m_stream;
    int m_pos;
    unique_ptr<char[]> m_buffer;
};

class Writer {
  public:
    Writer(const string& filename):
            m_stream(filename),
            m_pos(0),
            m_buffer(new char[kBufferSize]) {}

    Writer& operator<<(int value) {
        char digits[10];
        int nr = 0, q;
        do {
            q = value / 10;
            digits[nr++] = value - (q << 1) - (q << 3) + '0';
            value = q;
        } while (value);

        while (nr--) {
            m_buffer[m_pos++] = digits[nr];
            if (m_pos == kBufferSize) Flush();
        }

        return *this;
    }

    Writer& operator<<(char value) {
        m_buffer[m_pos++] = value;

        if (m_pos == kBufferSize) Flush();

        return *this;
    }

    void Flush(){
        m_stream.write(m_buffer.get(), m_pos);
        m_pos = 0;
    }

  private:
    const int kBufferSize = 32768;

    ofstream m_stream;
    int m_pos;
    unique_ptr<char[]> m_buffer;
};

using namespace std;

int n, m;
int tree[NMAX << 1];

void Build(){
    for (int i = n - 1; i; --i){
        tree[i] = max(tree[i << 1], tree[i << 1 | 1]);
    }
}
void Update(int poz, int val)
{
    tree[poz += n] = val;
    for (poz >>= 1; poz >= 1; poz >>= 1)
        tree[poz] = max(tree[poz << 1], tree[poz << 1 | 1]);
}

int Query(int st, int dr)
{
    int res = 0;
    for (st += n, dr += n; st <= dr; st >>= 1, dr >>= 1){
        if (st & 1) res = max(res, tree[st++]);
        if (!(dr & 1)) res = max(res, tree[dr--]);
    }
    return res;
}


int main()
{
    Reader fin("arbint.in");
    Writer fout("arbint.out");

    //#define fin cin
    //#define fout cout

    fin >> n >> m;

    for (int i = 0; i < n; ++i)
    {
        fin >> tree[i + n];
    }
    Build();

    for (int i = 0; i < m; ++i)
    {
        int t, a, b;
        fin >> t >> a >> b;
        if (t == 0)
            fout << Query(a - 1, b - 1) << '\n';
        else{
            Update(a - 1, b);
        }
    }

    fout.Flush();
    return 0;
}